It has been reported that N-(5-tert-butyl-isoxazol-3-yl)-N′-{4-[7-(2-morpholin-4-yl-ethoxy)imidazo[2,1-b][1,3]benzothiazol-2-yl]phenyl}urea (AC220) or a pharmaceutically acceptable salt thereof is effective in treating proliferative diseases in which FMS-Like Tyrosine Kinase-3 (FLT3) is involved, such as leukemia in one embodiment, and such as AML in another embodiment. See International Publication Nos. WO 2010/132787, WO 2007/109120, and WO 2009/038757.
AC220 dihydrochloride (2HCl) is currently being developed for treatment of AML. This compound has molecular weight of 663.6 and the following formula:

International Publication No. WO 2010/132787 discloses a spray-dried powder or a lyophilized powder of AC220 in combination with cyclodextrins (as a carrier), which is disclosed as an anti-gelling agent. In certain embodiments, the spray-dried powder or lyophilized powder comprises AC220.2HCl and HPBCD in a ratio of 1:5 to 1:20 by weight. It is further described in WO 2010/132787 that in certain embodiments, the spray-dried powder is dissolved (reconstituted) before use and administered in a liquid dosage form. WO 2010/132787 also discloses a formulation comprising a spray-dried powder of AC220.2HCl and HPBCD at a 1:10 ratio by weight, which is dissolved before use and administered orally in a liquid dosage form (hereinafter this liquid dosage form is sometimes referred to as “AC220 solution (1:10)”), see Examples 6 to 8. WO 2010/132787 further discloses solid preparations of AC220 for oral administration, for example, liquid capsules using AC220 and GELUCIRE™ 44/14 (lauroyl polyoxylglycerides), and capsules comprising AC220 and HPBCD in a ratio of 1:2 by weight in combination with mannitol and EXPLOTAB™ (sodium starch glycolate).
However, no tablets having bioavailability equivalent to that of the preparation that is dissolved before use comprising the spray-dried material of AC220.2HCl and HPBCD at a 1:10 ratio by weight (administered in a liquid dosage form: AC220 solution (1:10)) disclosed in WO 2010/132787 have been reported until now. Development of tablets which are excellent in dispersibility, dissolution, and stability and which can achieve the bioavailability equivalent to that of the preparation that is dissolved before use disclosed in WO 2010/132787, is desired.